Angina happens when there is not enough blood flow to the heart muscle. This is often a result of narrowing of the blood vessels that supply blood to the heart. Angina symptoms include chest pain or pressure. But you might feel other symptoms like pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly, or one or both shoulders or arms.

Stable angina occurs at fairly predictable times, usually with activity or exertion. It is relieved by rest and may continue without much change for years. Stable angina develops after a predictable amount of exertion or emotion and usually lasts 1 to 5 minutes.

A change in the usual pattern of stable angina means that the blood flow has become more impaired (called unstable angina). It is a warning sign that a heart attack may soon occur.